As a result of recent technological innovation, various information devices, for example, workstations (WSs) and general computers such as personal computers (PCs), are being developed and widely used.
Generally, information devices are configured such that the user is able to perform operations, for example, command input, by using a keyboard or a mouse or by various operation buttons, which are provided for the information devices as standard features.
Small and light information terminals, for example, cellular telephones and PDAs (Personal Digital Assistants), are also coming into widespread use. Accordingly, there is an increasing demand for exchanging data between such information terminals. For example, the user wishes to operate information devices installed in offices or households (for example, fixed computers, such as desk-top computers, other types of relatively large information devices, and information household electrical appliances), by using a cellular telephone or a PDA which is always carried by the user and is familiar to the user.
Generally, for implementing data exchange between devices, the devices are connected to each other by using cables.
However, wired connection makes the operation troublesome and complicated for the user, and is also impractical because the user has to prepare a connector compatible with each device to be communicated with. Additionally, in infrared data communication, for example, IrDA (Infrared Data Association), the viewing angle used in the infrared transmitter is narrow. Accordingly, data communication is easily interrupted due to the presence of an obstacle, for example, by the user inadvertently passing through the infrared transmission channel.
Recently, it has been suggested that a plurality of devices be wirelessly connected by using a technique such as a wireless LAN (Local Area Network), for example, IEEE802b.11, or short-distance wireless data communication such as Bluetooth. Since radio communication is nondirectional, the problem of interrupting transmission data due to an obstacle is not presented.
When communication is performed via a wired or wireless network, however, the user must input the address (or address information corresponding to the address) of a communicating device. Normally, since the user cannot memorize the address of each device, he/she prepares an address book in advance and manually inputs the address while referring to it. Accordingly, the operability of current wireless connection between devices is low and is impractical. For example, even when connecting a cellular telephone or a PDA owned by the user to a computer or another information device installed in front of the user, he/she must input the address of the communicating device.
Additionally, it is now assumed that the user wirelessly connects a cellular telephone or a PDA owned by the user to an information device installed in an office or a household, and then remotely controls the information device by using the cellular telephone or PDA, whose operation is familiar to the user. In this case, such a cellular telephone or PDA is not provided with an operating environment compatible with the information device. It would be convenient if a cellular telephone were provided with operation information, such as a GUI (Graphical User Interface) specially used for the operations of household electrical appliances, for example, televisions or audio devices. It is not practical, however, that the operation information of each device is included in a cellular telephone as a standard feature. That is, when operating another device via a portable terminal, the usability of the current system is low.